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边坡治理是水库工程建设的难题之一,我国已经建设了相当数量的水库工程,但由于水库建设和运行期间产生人为干扰,水库涉水边坡的稳定性以及变电站的正常运行都会受到一定程度的影响,严重时还会造成一些边坡出现滑塌等问题。通过工程实际案例,分析了边坡主要不利因素,利用极限平衡法计算不同工况下白稳定系数,对边坡进行稳定性分析,提出可以利用抗滑桩、建立排水系统等措施提高抗滑力,最后得出地震作用是影响边坡稳定性最大的因素。 相似文献
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某煤矿采掘场非工作帮边坡为软岩高边坡,为分析边坡是否存在潜在安全隐患而影响施工进度及施工安全,进行了非工作帮边坡的稳定性分析。采用Geo-studio软件中的Slope/W模块建立了边坡的计算模型,并用Bishop法和Morgenstern-price法对暴雨工况和暴雨叠加地震工况进行计算,得出边坡的稳定性系数。推测的滑面计算结果与边坡稳定性评价的标准进行对比,发现计算结果与现场勘察后预测结论基本一致。该边坡整体稳定性为基本稳定。更多还原 相似文献
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文章针对南水北调高填方渠道边坡,将莫尔-库伦准则与概率可靠度理论相结合,建立了黏性土高填方渠坡土壤塑性变形失稳分析的可靠度模型,研究了渠坡内土壤塑性变形失稳的区域、形态及其对渠坡稳定的影响;研究了土壤特性指标变异对其塑性稳定可靠指标的影响。 相似文献
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本文依据凤翔县白荻沟水库除险加固工程初步设计大坝土工试验资料,结合碾压式土石坝设计规范《SDJ218~84》及《SL218—2001》对稳定计算中C、φ指标的选用要求,分别对该工程大坝边坡稳定进行了计算,最后提出关于土石坝边坡稳定计算中C、φ指标选用的一些认识,为类似工程设计提供一些经验。 相似文献
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利用土水特征曲线,建立了非饱和土含水量与强度的关系式,并用其对某高速公路残积土高边坡进行稳定分析。通过土体含水量在高边坡稳定分析中的应用,提出把含水量作为边坡稳定分析的重要参数,采用土体非饱和强度参数计算得到的边坡稳定安全系数比采用饱和强度参数得到的边坡稳定安全系数大,更接近边坡实际工况。 相似文献
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根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。 相似文献
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The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects. 相似文献
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Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river. 相似文献
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In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment. 相似文献
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V. K. Konovalov O. V. Yashkin V. V. Ermakov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2008,42(2):105-109
A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed
in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash
and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers
of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional
components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect
dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system,
configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants
of dry ash utilization and the advantages of producing of size-separated particles are considered.
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Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008). 相似文献
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Peter B. Bayley 《河流研究与利用》1991,6(2):75-86
The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed. 相似文献